1. Field of the Invention
The present invention relates generally to vehicle trailers. More specifically, the present invention is an adjustable height trailer having a fifth wheel, an adjustable height forward hitch, and an adjustable height rear axle.
2. Description of the Related Art
The floors of vehicle trailers are conventionally relatively high above the underlying surface, to provide sufficient ground clearance when underway. When such trailers are parked for loading and unloading, the relatively high trailer floor complicates such loading and unloading. Typically, powered machinery (e.g., a fork lift, etc.) is necessary to facilitate the job, with larger trailers and cargos.
So-called “fifth wheel” trailers, i.e., trailers having one or more rear axles with the forward support being by means of a hitch mounted on a plate or “wheel” on the back of the towing vehicle, are commonly used for transport of larger and/or heavier cargo. Most people are familiar with the conventional semi-trailer pulled by a truck tractor, with this assembly using the fifth wheel trailer principle. Smaller fifth wheel trailers are also in relatively common use for towing by smaller vehicles, e.g., pickup trucks and smaller flatbed trucks equipped with a fifth wheel hitch.
Articulating or adjustable height rear suspension systems have been developed for such trailers, but such systems only serve to lower the rear of the trailer. The forward end of the trailer remains elevated on the fifth wheel hitch of the towing vehicle, unless the trailer is unhitched from the towing vehicle to allow the forward end of the trailer to be lowered. This is a cumbersome procedure that requires an additional step in order to lower both ends of the trailer to ground level.
A relatively high trailer floor is even more inconvenient and cumbersome in a livestock trailer. Large animals, and particularly horses, are uncomfortable when presented with relatively narrow sloping ramps and similar boarding and unloading fixtures. The uncertain footing sensed by the animal, along with possible vehicular traffic and commotion in the area in many circumstances, may “spook” the animal to the extent that the animal injures itself on or in the trailer, or in nearby traffic.
Another common problem with livestock trailers is the provision of a single rearwardly disposed door for loading and unloading. Animals are generally loaded head first through the door, but then must back out of the trailer when unloading. This, in combination with a sloping ramp in a conventional trailer, gives an animal even more cause to be nervous during the unloading operation. This is even true in larger trailers, with their multiple stalls for holding a number of horses or other large animals.
Attempts have been made in the past to facilitate the loading, unloading, and transport of a number of larger animals in a single trailer. An example of such is found in Japanese Patent No. 2002-137678, published on May 14, 2002. This reference describes (according to the drawings and English abstract) a horse trailer having three forwardly disposed stalls and three rearwardly disposed stalls. The stall doors have removable drop-pin type hinges that allow the doors to pivot as desired and also serve as latches to secure the doors to one another when closed.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. Thus, an adjustable height trailer solving the aforementioned problems is desired.